N (thiophenalkyl) arylamines



Patented Feb. 5, 1952 N (THIOPHENALKYL ARYLAMINES John H. McCracken,Tulsa, Okla., assignor to So cony-Vacuum Oil Company, Incorporated, 'a

corporation of New York No Drawing. Original application May 28, 1947,

Serial No. 751,124. Divided and this application November 6, 1948,Serial No. 58,799

7 Claims.

were well known. Many of these were known to be useful addition agentsfor mineral oil, mainly for the purpose of stabilizing the oil againstoxidation and deterioration. Also known were alkyl substitutedthiophenes and haloalkyl substituted thiophenes such as 2methylthiophene, 2 chlormethylthiophene. The corresponding ethyl, propyland butyl com pounds can be prepared. These are not known to have beenpreviously used as mineral oil addition agents.

According to the present invention it has been discovered that aryl orquasi-arylamines can be reacted with haloalkylthiophenes to produce newcompounds that may be generally designated as N(thiophenalkyl)arylamines or N(thiphenalky1) quasi-arylamines. These compounds,especially the N(thiophenmethyl)naphthylamines, when added in smallamounts to mineral oil, have been found to markedly improve itsproperties, particularly its stability against oxidation anddiscoloration. Ordinarily, the desired improvement can be accomplishedby the addition of 1% or less of the new improving agents, but in someinstances as much as is desirable.

As examples of the new class of compounds to which this inventionrelates, the following compounds have been prepared.

Example I Chloromethylthiophene was prepared by the procedure outlinedby Blicke and Burckhalter, Journal of the American Chemical Society,vol. 64, page 477' (1942), except that the procedure was simplified byusing liquid hydrochloric acid instead of gaseous hydrochloric acid.

A 3-necked flask of suitable size, fitted with a mechanical stirrer andtwo dropping funnels was used for the reaction. In it was placed 85 cc.(1 mol) of concentrated hydrochloric acid. The reaction flask was cooledin an ice bath and 40 g. (0.5 mol) of 37% formaldehyde solution and 42g. (0.5 mol) of thiophene were added dropwise from the funnels over aperiod of two hours. The mixture was stirred for an additional hour.

M The lower layer was drawn off and theupper layer diluted with an equalvolume of water and extracted with ether. The extract was combined withthe lower layer and the resultant product washed three times withdistilled water, dried over calcium chloride, the ether distilled off,and the residue distilled under reduced pressure.

There resulted 10 g. (0.12 mol) of chloromethylthiophene boiling at74-80 C. at 16 mm. pressure, and 5 g. of dithienylmethane boiling at-128 C. at 4 mm. pressure. The freshly distilled chloromethylthiopheneis a water-White liquid with an odor like that of benzylchloride.

By fractionating the ether distillate and the forerun of the vacuumdistillation, 11 g. (0.13 mol) of thiophene were recovered. Thus, theconversion of thiophene to chloromethylthiophene was 33%.

Solutions of 36 g. (0.26 mol) of alpha-naphthylamine in 100 cc. ofanhydrous ethyl ether and 10 g. (0.12 mol) of chloromethylthiophene in25 cc. of anhydrous ethyl ether were mixed and allowed to stand at roomtemperature for 24' hours. The precipitated naphthylamine hydrochloridewas filtered off and the ether solution washed with water. After dryingand distilling off th ether, the product was a very dark purple oil.This will later be designated product A.

Product A was purified by .distillation at 4 mm. pressure. A smallfraction of alpha-naphthylamine boiling at -180 C. was discarded and thefinal product collected at 230260 C. The product was a viscous oil,light orange in color when freshly distilled but darkening on exposureto air. Its boiling point and other characteristics clearly indicate itto be a new chemical compound and it follows logically from theoreticalconsideration and the characteristics of the product that it was N-(2-thiophenmethyl) -alphanaphthylamine. This purified product will laterbe designated product B.

Example II Chloromethylthiophene prepared as in Example I was reactedwith beta-naphthylamine in the same manner as it was reacted withalphanaphthylamine in Example I. The results were substantially the sameexcept that the product boiled at -210 C. at 1.5 mm. pressure. Thisproduct is apparently N-(2-thiophenmethyD- beta-naphthylamine.

Example III 135-150 C. at 2-3 mm. pressure.

Example IV In a similar manner chloromethylthiophene' was reacted withbenzylamine to produce N-(2- thiophenmethyl).-benzylamine, the productboiling at 155-160 C. at mm. pressure.

Example V One of the corresponding di-substituted compounds was preparedby reacting one mol of N- (2-thiophenmethy1) -alpha naphthylamineprepared according to Example I with one mol of chloromethylthiophene inether solution. The resultant compound was apparently N.N-bis(2-thiophenmethyD-alpha naphthylamine. This compound was a glassy, waxymass which was left after distilling out unreacted materials up to 225C. at 5 mm. pressure. It had a sulphur content of 17.8% as against acalculated sulphur content for the pure compound of 19.2%, but this wasdoubtless due to the presence of a certain percentage of themono-substituted compound, as an impurity. The compound was diflicult topurify due to its high molecular weight.

The new compounds have, among other things, been tested foreffectiveness as addition agents to mineral oils in percentages rangingfrom 0.05% to 0.2% and the mineral oil compositions show definiteimprovement as to color and neutralization number under test. Thisimprovement is especially marked when compounds of this series are usedwhich contain a naphthalene nucleus to which is directly attached anitrogen atom substituted by one or more alkylthiophene radicals.

The following are examples of mineral oils stabilized by the addition ofvarious of the new compounds. The oils used in the following exampleswere:

Vise. Flash 011 St. 18691 P oitnt, Gravlty Example VI Oil A is a highlyrefined oil suitable for use in transformers. This oil was prepared bytreating a Coastal distillate with 40 pounds of 98% sulphuric acid and180 pounds of 103% oleum, per barrel. This was followed by washing andpercolating through clay. This type of oil tends to form acidic productson oxidation. The oil was quired to neutralize the acids formed in agram of oil.

Neutrali- Composition zation Number Oil A 1s. 5 Qua-+02% of product A ofExample I- 0. 02 Qua-+01% of product B of Example I. 0. 04 Oil A+0.l% ofproduct of Example V 0. 02

(iii

4 Example VII Motor oils, and especially those refined by certainsolvent-extraction methods tend to oxidize when submitted to hightemperatures. Under these conditions, they tend to form products whichare corrosive to metal bearings. This corrosive action may be quitesevere with certain types of bearings, such as those having thecorrosion susceptibility of cadmium-silver alloys, and may cause theirfailure within a relatively short period of time.

The following test was used to determine the corrosive action of a motoroil on an automobile connecting rod bearing. Oil D consisted ofPennsylvania neutral and residuum stocks separately refined by means ofchlorex and then blended to give an A. S. E. 20 motor oil. The oil wastested by adding a section of a bearing containing. a cadmium-silveralloy surface and weighing about 6 g. and heating it to 175 C. for 22hours while a stream of air. was bubbled against the surface of thebearing. The loss in weight of the bearing during this treatmentmeasures the amount of corrosion which has taken place. The followingresults were obtamed:

Loss in Composition Weight of Bearing, m1.

Oil D 29 Oil D+0.2% of product A of Example I nil Oil D 24 Oil D+0.l% ofproduct A of Example I 0 Oil D+0.05% of product A of Example 1.. 0 Oil D34 Oil D+0.05% of product B of Example 1-. 0

Example VIII Oil B was a distillate from a Rodessa crude whichwasrefined with furfural, dewaxed and filtered. This oil was of the typesuitable for use in turbines. The oil was tested by bubbling 0.3 literof oxygen per hour through 25 milliliter samples of the oil in thepresence of copper and iron spirals. 5 milliliters of water were addedto each sample which were kept at a temperature of 99 C. A refluxcondenser was provided for each Oil 0 was a mixed Mid-Continent andCoastal distillate that had been refined by treatment with 70 pounds of98% sulphuric acid per barrel. After the acid treatment the oil wasneutralized, washed and percolated through clay. Oil C and oilB weretested by the Brown-Boveri turbine oil test method which involvesheating a test sample of the oil in the presence of a piece of copperfoil at a temperature of C. in air, for '72 hours, after which the colorand neutralization number are determined. These are indicative of theextent to which the oil is affected by oxidation. The following resultswere obtained:

Color N eutrali- Example X Oil B and oil C were also tested by thefollowing method which is used to evaluate oils for use in turbines.

This method consists of placing 25 milliliters of the oil in each ofseveral 150 X 25 millimeter test tubes. Each of the tubes is thencovered with a glass lid and provided with a 5 millimeter delivery tubeextending to the bottom of the tube. About one gram of iron nails and acopper foil are then added to each tube. During the test, thetemperature is maintained at 91 C. and clean, dry air is bubbled throughthe oil at a rate of 5 liters per hour. Every 24 hours 2 milliliters ofdistilled water are added to each tube. Samples are recovered from eachtest tube at varying periods of time and are examined for acidity(neutralization number) and color. The following results were obtained:

N eutrali- Composition Hours gg ga zatlon Number 011 B 166 50 8. 3 OilB+0.2% of Product A of Example I 164 0.8 0. 02 Do 474 8 0.02 OilB-i-O.1% of Product B of Example I 960 1. 6 0. 02 Oil B+0.5% of ProductB of Example I 330 1 0.02 Do 720 2. 3 0. 04 D 1, 122 6 0. O2 OilB+0.05%of the produ tof Example 160 20 4. 7 O 210 17 7.0 011 C 240 110 2. Do336 400 16. 0 011 C+0.2% of Product A of Example I 332 75 2. 4 Do 408 803. 7 Oil O+0.1% of Product B of Example I 331 20 0.1 Do... 956 115 4. 6011 C 162 19 1. 0 Do"... 312 62 3.9 011 C+0.l% of to Example I..." 168 30. 2 Do 331 20 0.1

This application is a division of application Serial Number 751,124,filed May 28, 1947, now U. 5. Patent No. 2,518,351, issued August 8,1951.

What is claimed is:

1. As new chemical compounds, N-(2-thiophenmethyl) alpha-naphthylamine.

2. As new chemical compounds, N-(Z-thiophenmethyl) beta-naphthylamine.

3. As new chemical compounds, N-(Z-thiophenemethyl) -aniline.

4. As new chemical compounds, N-(Z-thiophenemethyl) -benzy1amine.

5. As a new chemical compound, N.Nbis(2- thiophenmethyl)alpha-naphthylamine.

6. As a new chemical compound, an amine having the formula:

s H X o-N H l I! l T wherein X is a radical selected from the groupconsisting of hydrogen and Z-thenyl, and T is a radical selected fromthe group consisting of alpha naphthyl, beta naphthyl, phenyl andbenzyl.

'7. As new chemical compounds N-(thiophene methyl) naphthylamine.

JOHN H. MCCRACKEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,816,911 Pfleger Aug. 4, 1931OTHER REFERENCES

6. AS A NEW CHEMICAL COMPOUND, AN AMINE HAVING THE FORMULA: